Various forms of slat type window blinds are known, wherein a blind assembly is formed of a series of parallel horizontally extending blind slats which are suspended to across a window opening. One form of slatted blind, known as a venetian blind, typically comprises blind slats of a simple curved cross-section for interior use, being located immediately adjacent to a window on the interior side. Such blinds are not generally exposed to any significant loads, and hence are quite simple and low weight in nature. Slatted blind systems are also utilised on the exterior of buildings, located immediately adjacent the window on the exterior side. Such exterior slatted blind systems may be subject to significant wind loads, and hence structural considerations that do not affect interior blind systems must be contemplated in any blind slat design. Slatted blind systems are intended to allow for natural light to enter through the window when the blind is in the lowered and open configuration in which the individual blind slats are spaced. Energy usage from powered light sources can be reduced if the blind is able to adequately reflect light from the individual slats and project that reflected light onto work surfaces located a distance away from the window covered by the blind. Typical available slatted blind systems for exterior applications either provide inadequate light projection and/or suffer from structural deficiencies in high wind applications.